Process for preparing fiber from cornstalks and analogous pithy plants.



UNITED- STATES PATENT OFFICE.

ALBERT G. MANNS, OF CHICAGO, ILLINOIS, ASSIGNOR, BY DIRECT AND MESNEASSIGNMENTS, TO FOOD & FIBER PRODUCTS COMPANY, OF

CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

PROCESS FOR PREPARING FIBER FROM CORNSTALKS AND ANALOGOUS PITRY PLANTS-Application filed April 14,

Letters Patent. 1905. Serial No. 255,640.

Patented Jan. 30, 1906.

1'0 all whom it may concern.-

Be it known that I, ALBERT G. Mamas, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Process for Preparing Fiber fromCornstalks and Analogous Pithy Plants, of which the following is aspecification.

This invention relates to an improved process for preparing fiber fromcornstalks and analogous pithy plants; and among the salient objects ofthe invention are to produce an improved quality of fiber, to subjectthe material to a treatment which will remove the non-fibrous substance,including coloringmatter, to a lar e extent before the material issubjected to t e reducin action of disintegrating chemicals, to pro ucea pulp which is of more uniform quality and more. free from shive, toeconomize either in the amount of reducing chemicals or the timeemployed in bringing the fiber to its completed condi- 'tion, or both,to reduce the amount of bleaching agents and time of bleaching required,to provide a process which enables certain valuable constituents of thematerial other than the fiber to be separated out and saved withoutinterfering with the series of steps embodying the process, and ingeneral to provide a simple and improved process for the purposedescribed.

. The reduction of cornstalksand analogous pithy plants to form fibersuitable for papermaking and analogous uses is not new. Heretofore ithas been customary to take the cornstalk or analogous material,sometimes in shredded, comminuted, or partially comminuted form andsometimes whole or without mechanical division, and as the first step ofthe actual reducing treatment have subjected the raw material to acooking process in a chemically-charged reducin liquor, usually acaustic solution. Diflicu ty has been experienced in securing a properreduction of the material,-because of the widelydifl"erent character ofthe shell and pith portions, because of the pigment contained in thematerial, and for other reasons unnecessary to enumerate. Obviously whenthe raw material is placed directly in a chemical reduc ingsolution andcooked all of those constituents of the plant susceptible to destructionby such treatment are lost. I have discovered that by subjecting thematerial to a preliminary extracting process in conjunction with waterand heat a very large proportion of the substance of the plant isdissolved and may be separated therefrom, thereby effecting a long stepin the direction of the ultimate reduction to fiber and enabling thesoluble matters thus removed to be utilized in the production of a foodextract or for other purposes.

In carrying out my improved process I first place the cornstalks,bagasse, or analogous material in a suitable vessel together with asufficient uantity of water to submerge the material and then applyheat, and thereby subject the material to an extracting process, wherebythe constituents of the ma terial soluble in water are dissolved and setfree. I have found in practice that the stalks may be advantageouslycooked for from three and one-half to four hours at the temperature ofboiling water under atmosheric pressure-i 0., about 212 F ahrenheit. Ofcourse the sameend may be secured by a longer period of cooking and alower temperature, or the somewhat shortened by coo ing in a closedvessel under higher temperature-41. e., by cooking with superheatedsteam. This cooking process is efiective whether the stalks be shreddedor mechanically divided or treated whole or in the condition in whichthey came from the field. After the mass has been cooked or subjected tothis extracting step drained away or otherwise separate irom the mass ofthe material, and the latter will be found to be in a soft more or lesspulpy condition and very considerably lighter in color than during theinitial stage of the treatment.

As before stated, the extract'liquor may be separated from the mass bydrainage; but it may also be separated by expressing or other- It isknown that cornstalks, bagasse, and analogous giant members of the genusgram'inew are made up lar ely of two distinct and radically differentkinds of cells available for making fiber. The shell of the stalk ischiefly composed of longfilamentaryfibers,

the plant. The pithy portions of the plant process may be which are themost indestructible fibers of.

for a sufficient length of time the li nor is I are composed chiefly ofrelatively lar e irregular or ovoidal shaped shells, who under themicroscope are seen to be hollow bladderlike bags, the interiors ofwhich are more readily destructible than the outer walls. Theseparenchymatous cells are much more readily destructible than thefilamentary cells, and I have discovered that when subjected to theaction of a reducing liquor, such'as caustic soda, these cells are quitereadil destroyed, the interior portions of the cells eing apparentlyfirst dissolved away, thus making the walls thinner and thinner untilfinally the cells rupture and completely disinte rate.

I have further discovered that i the raw stalks taken in their naturallydry or approximately dry condition be placed directly in a reducingsolution and given a treatment sufficientl drastic to effectdisintegration of the interce lular structure a very considerablepercentage of the pith-cells will be destroyed y the time this necessarydisintegration has been reached. I have also demonstrated that bysubjecting the mass to the preliminary cookin and extracting in waterhereinbefore described the subsequent reduction by the use of causticsoda or other suitable reducing liquor may be effected with a muchmilder treatment with much more uniform results and Without destroyingany considerable proportion. (if any) of the ith-cells.

It will be obvious from the oregoing that the successful carrying out ofthat step of my present process which consists in cooking the mass in achemical reducing solution depends upon-an intelligent effort to securethe desired result-namely, to effect the complete disinte ation of theintercellular matter, setting cc of the ultimate fiber, both filamentaryand parenchymatous, without jgligstroying a large percentage of thisultimate The fibrous mass is therefore next subjected to a cookingtreatment in a suitable vessel with the usual reducing rea ents, such asa caustic-soda solution or a sul urous-acid solution, depending upon thecharacter of fiber it is desired to produce. The length of time requiredto reduce the fibrous material to a disintegrated condition in which thefiber is freed from the intercellular structure is much less than thatordinarily required where no preliminary cooking treatment has beengiven it. Moreover, it is found that a much weaker reducing solution iseffective than Where the plant is reduced directly from its raw state bycooking in the reducing solution in the first instance and the reductionto a disintegrated condition is much more uniform, doubtless owing tothe fact that the shell portions, and particularly the nodes, are by thepreliminary cooking thoroughly softened and partially disintegrated. Inpractice I have found that a saving of approximately one-third of thereducing agent may be effected or with the use of a stronger solution acorresponding reduction in time may be effected, it being wellunderstood by those skilled in the art that the strength of the reducingsolution and the temperature largely governs the length of time requiredto complete the treatment. For example, in reducing with caustic-sodasolution I have found that in treating cornstalks a cooking treatmentextending over five to ten hours at a pressure of ap roximately onehundred pounds with a so ution of about fifteen-per-cent. strength iseffective in reducing the mass to a disintegrated condition withoutdestroyin any considerable proportion of the pith-eel s. The treatmentmay be continued somewhat longer under the same conditions withoutreducing the yield much, or a somewhat stronger reducing solution may beused for a corresponding shorter time or at a correspondingly lower temerature without materially reducing the yiel On the contrary, if asolution of double the strength mentioned be employedand the treatmentcontinued for from six to ten hours it will be found that the grossyield of fiber will be very materiallylessened, and this loss will bechiefly due to the destruction of the pith-cells. The fact that thereduction is more uniform is evidenced by the absence of anyconsiderable percentage of shive at the time when the mass has reached adisintegrated condition and is further evidenced by the increasedpercentage of fiber recovered from a given amount of material. Each ofthese two kinds of fiber possesses distinct characteristics and lendspeculiar characteristics to the paper roduced therefrom. Sometimes it isdesirab e to separate the two kinds of fiber, and when this is the casethe next step of the process is to effect a separation of the mass byrepeated or continued washing and screening, a'suitable screen orscreens being used which will permit the ovoidal cell fiber to passthrough the machine while retaining the filamentary fiber. This step ofthe process is best effected by the use of a machine or apparatus whichmaintains a repeated or constant agitation of the mass while it is beingpassed over and through the screen, the pulp being maintained in arelatively dilute condition, so as to facilitate the flowing out andpassing through the screens of the ovoidal fiber.

The two kinds of fiber thus separated are in condition for use for somepurposes without further treatment; but ordinarily it is necessary tobleach the fiber, and this is accomplished in the usual way by agitatingthe fiber in a bleaching solution.

It is to be noted that owing to the fact that a large percentage of thepigment or coloringmatter contained in plants of this character issoluble in water, especially in hot water, the fiber is of relativelylight color before described except sums bleaching and accordin 1y aweak bleaching solution or a short period of treatment is sufficient'toeffect the com lete bleaching of the fiber. It follows that I not onlyeffect a substantial saving at this stage of the treatment, but I havealso found that the character of the fiber as finally produced is imroved. This is doubtless due to the more uni duction and the use of lessdrastic treatment both in the reducing liquor and in the bleach.

While I have described the process as preferably carried out, yet itwill be understood by those skilled in the art that the process may bevaried without departing from the spirit of the invention, andaccordingly I do not limit myself to the precise details herein to theextent that they are made the subject of specific claims.

Iclaim as my invention 1. The process of reparing fiber from cornstalks,bagasse and same genus, which consists in first practically mass fromwater-soluble constitutents by subjecting the raw material 1 thereinfrom s and then se disintegration of the to the action of a heatedhydrous bath to efiect dissolution of said constitutents and theseparating the solution from said mass, next subjecting the fibrousmaterial to a digesting cook in a suitable reducin liquor drastic enoughto effect moderatefy rapid intercellular tissues and incrustaceousmatters but not drastic enough to effect at the same time thedestruction of any large proportion of the pith-cells, continuing thisdigesting treatment under controlled conditions until the pith andfilamentary cells are substantially set free from the connective tissuesand finally se arating and recovering said cells from the disintegratedmass.

2. A process of preparing fiber from cornstalks, bagasse and analogouspithy plants which consists in subjecting the raw material to apreliminary extracting and softening rocess with water, separating theextracting iquor and extracts contained in solution the fibrousmaterial, then cooking the fibrous material in a usual reducing liquoruntil the mass is disintegrated and the fibers freed from theintercellular structure arating the two kinds of fiber-by Washing'anscreening.

3. The process of reparing fiber from cornstalks, bagasse and analogousplants of the same genus which consists in first practically freeing thefibrous mass from water-soluble constitutents by subjecting the rawmaterial to the action of a heated bath of water or steam to. effectdissolution of said constituents and then separating the solution fromanalogous plants of the trolled conditions until the disintegration ofsaid mass, next subjecting the remaining fibrous material to a digestingcook under pressure in a suitable reducing iquor drastic enough toeffect moderately rapid disintegration of the intercellular tissues andincrustaceous matters but sufiiciently mild to prevent effecting at thesame time the destruction of any large proportion of the pith-cells,continuing this digesting treatment under conpith and filamentary cellsare substantially set free from the connective tissues and finally searating and recovering said cells from the isintegrated mass.

4:. The process of reparing fiber from cornstalks, bagasse an analogousplants of the same genus, which consists in first practically freeingthe fibrous mass from Water-soluble constituents by subjecting the rawmaterial to the action of a heated hydrous bath and effectingdissolution of said constituents and then se arating the solution fromsaid mass, next su jecting the fibrous material to a digesting cook in asuitable reducing liquor drastic enough to effect moderately rapiddisintegration of the intercellular tissues and incrustaceous mattersbut sufliciently mild to prevent at the same time the destruction of anylarge tinuing this digesting treatment under controlled conditions untilthe pith and filamentary cells are substantially set free from theconnective tissues, then separating the fiber from the reducing solutionand finally treating the fiber in a bleaching solution.

5. The process of preparing fiber from cornstalks bagasse and analogousplants of the same genus, which consists in-first practically freeingthe fibrous mass from the water-soluble constituents by subjecting theraw ma terial to the action of a heated hydrous bath and thus effectingdissolution in said constituents, then so arating the solution from saidmass, next su eating the fibrous mater al to a digesting coo in asuitable reducing liquor drastic enough to effect moderately rapid theintercellular tissues and incrustaceous matters but mild enough toprevent the destruction at the same time of any large proportion of thepith-cells, continuing this digesting treatment under controlledconditions until the pith and filamentary cells are substantially setfree from the connective'tissues, then separating the fiber from thereducing solution and finally beating the fiber.

- ALBERT G. MANN S. Witnesses:

11.13pm, F. H. Emosou.

proportion of the pith-cells, con-

